Compound Interest Calculator
Savings growth with compounding.
Enter your values in the interactive calculator to see an instant result. Calculations run in your browser, without an account.
Results are estimates for educational use; confirm important decisions with appropriate experts.
Compound interest year-by-year projection
Optional advanced model. Compare deposit timing, compounding frequency, and an assumed inflation rate. Results are hypothetical, not guaranteed returns.
Estimate only. Review the assumptions and limitations on this page before making financial or academic decisions.
Formula • Worked example • Interpretation
Compound interest formula and examples
Compounding means that interest can earn additional interest in later periods. More frequent compounding usually leads to a slightly higher effective annual yield for the same nominal rate.
Calculation method
Worked example
$1,000 at 5% nominal annual interest compounded monthly for 10 years becomes about $1,647.01 before fees and taxes, without new deposits.
What your result means
The assumed annual rate and compounding frequency are distinct. An advertised APY already includes compounding, so do not compound the APY a second time.
Tips for better calculations
Compare otherwise identical scenarios at 3%, 5% and 7% rather than treating any one rate as guaranteed.
Assumptions and limitations
Taxes, account fees, variable yields, and the timing of recurring deposits can change results. Negative rates or contributions may require special treatment.
SiCalcs tools provide estimates and educational calculations; they do not replace professional financial, medical, tax, or legal advice.